Motor fuel containing an octane appreciator



United States Patent ()fiice 3,35%,87 Patented Dec. 19, 1967 No Drawing.Filed Jan. 6, 1959, Ser. No. 785,137 10 Claims. (Cl. 44-69) Thisinvention relates to a hydrocarbon fuel composition of high octanerating. More specifically, it involves the discovery that the octanerating of leaded gasoline fuel is substantially improved by the additionof aldehyde dialkanoates.

The recent increases in compression ratios of automobile engines haveplaced a severe strain on petroleum refiners to produce fuelshaving theoctane rating demanded by these engines. Premium fuels at the presenttime have a Research Octane Rating between 97 and 100 and it has beenpredicted that premium fuels will require octane ratings between 105 and110 five years from now in order to satisfy the octane requirements ofthe high compression automotive engines predicted for that date. Inorder to produce premium fuels of octane ratings of 97 and above, it hasbeen necessary for refiners to rely heavily on catalytic refiningoperations such as fluid catalytic cracking, catalytic reforming,alkylation and catalytic isomerization.

Catalytic cracking and catalytic reforming, which are the most widelyused refining operations in the production of high octane fuels, producesubstantial quantities of aromatics; catalytic cracking also produces asubstantial amount of olefins. It is well known that olefins andaromatics, although possessing high octane ratings have a poorerresponse to organo-lead compounds such as tetraethyl lead than saturatedaliphatic gasoline components. Accordingly, as the aromatic and olefiniccontent of the gasolines have increased to meet the octane levelsrequired by modern automotive high compression engines, the leadresponse of the resulting fuels has diminished. Stated another way, theoctane increment obtainable by the addition of an organo-lead compounddecreases as the aromatic and olefin contents of the base fuel increase.The subject invention involves the discovery that the octane rating ofleaded motor fuels containing a substantial concentration of high octanearomatic and/or olefinic components is markedly improved by the additionof a small amount of an aldehyde dialkanoate.

In our commonly assigned copending application Ser. No. 689,466 filedOct. 11, 1957, it is disclosed that hydrocarbyl monocarboxylic acidssubstantially raise the octane rating of a motor fuel containing anorgano-lead antiknock agent in a substantial concentration of highoctane components which may be aromatic hydrocarbons, olefinichydrocarbons, or mixtures thereof. Another commonly assigned copending aplication, Ser. No. 699,944 filed Dec. 2, 1957, discloses that t-alkylesters of monocarboxylic acids have a similar octane appreciating actionon leaded fuels of prescribed composition. This invention involves thediscovery that another class of esters are effective octane appreciatorsin leaded fuels of prescribed composition.

The high octane hydrocarbon motor fuels of this in vention comprise highoctane components including a substantial concentration of aromatichydrocarbons, olefinic hydrocarbons, or mixtures thereof, an organo-leadanti-knock agent, and aldehyde dialkanoates in a concentration of atleast 0.1 volume percent of the fuel.

The action of aldehyde dialkanoates in raising the octane rating ofgasoline is characterized by several unusual features. In the firstinstance, the aldehyde dialkanoates appear to be ineffective in raisingthe octane rating of gasolines unless an organo-lead anti-knock agent,normally tetraethyl lead, is a component of the gasoline mixture.

The second unusual characteristic of the action of aldehyde dialkanoatesin appreciating the octane rating of gasolines is the fact that anequivalent concentration of additive appears to cause a greater octaneimprovement above the 100 octane level than below the 100 octane level.

The third unusual feature of the action of aldehyde dialkanoates is thatthey appear to have substantially no effect on the octane rating of agasoline consisting essentially of saturated aliphatic hydrocarbons eventhough an organo-lead anti-knock agent is present. Since organoleadanti-knock agents exert their greatest octane appreciation inpredominantly saturated paraffiuic base hydrocarbon gasolines and havethe least effect on the octane rating of aromaticand olefin-richgasolines, the present invention neatly complements tetraethyl lead asan octane improver. Aldehyde dialkanoates have their minimum effectwhere tetraethyl lead has its maximum effect and exert their maximumeffect on octane values where tetraethyl lead has its minimum effect.

The novel fuel compositions of this invention have a minimumconcentration of aromatic and/or olefin components of at least 10 volumepercent. The aromatic and/or olefin components of the motor fuel of theinvention can constitute as high as 100 volume percent thereof butusually comprise between 20 and volume percent. The minimum 10 percentconcentration is necessary for aldehyde dialkanoates to exert asignificant octane improvement.

The aromatic components of the motor fuel of the invention are generallysupplied by catalytic reforming or catalytic cracking operation.Catalytic reformate is particularly high in aromatics. The olefincomponents of the motor fuel of the invention are derived either fromthermal cracking, catalytic cracking or polymerization.

The organo-lead reagent necessary for the action of aldehyde alkanoatesas octane improvers is a tetraalkyl lead compound of the class known topossess anti-knock action. Tetraethyl lead is universally used as anantiknock agent but other tetraalkyl lead compounds such as tetramethyllead, tetrabutyl lead, tetraamyl lead, tetrapropyl lead, etc., possessanti-knock properties and may be used in the fuel compositions of theinvention in conjunction with aldehyde dialkanoates.

The tetraethyl lead mixtures commercially available for automotive usecontain an ethylene chloride-ethylene bromide mixture as a scavenger forremoving lead from the combustion chamber in the form of volatile leadhalides. Tetraethyl Lead Fluid is a commercial product comprisingtetraethyl lead, ethylene chloride and ethylene bromide, the later tworeagents being present in amounts equivalent to 1.0 theory and 0.5theory, respectively, where theory is the stoichiometric amount requiredfor reaction with the lead content of the tetraethyl lead.

The organo-lead reagent is present in the fuel compositions of theinvention in concentrations between 0.5 ml. per gallon up to thestatutory limit of organo-lead reagent concentration which, at thepresent time, is 3 ml. per gallon in the case of automotive fuel and 4.6ml. per gallon in the case of aviation fuel. The usual concentration oftetraethyl lead is between 1 and 3 ml. per gallon in automotive gasolineand 2 to 4.6 ml. per gallon in aviation gasoline.

The aldehyde dialkanoates which are effective in increasing the octanerating of an aromatic and/ or olefincontaining leaded gasoline have thegeneral formula: RCH=(OOCR) wherein R is selected from the groupconsisting of a hydrocarbyl radical containing 1-12 carbon atoms and afuryl radical and R is an aliphatic hydrocarbyl radical containing 1-12and preferably 1-8 carbon atoms; the two Rs can be the same or differentaliphatic h-ydrocarbyl radicals. The aldehyde dialkanoates effective asoctane appreciators are prepared by reacting an aldehyde such asacetaldehyde or benzaldehyde with acetic anhydride in the presence of anacid catalyst such as concentrated sulfuric acid.

Aldehyde dialkanoates effective as octane appreciators in the fuelcompositions of the invention are the following: Benzaldiacetate,benzaldipropionate, benzaldibutyrate, -.benzaldi-Lethylhexanoate,benzaldilaurate, acetaldehyde diacetate, acetaldehyde dipropionate,acetaldehyde dihexanoate, isobutyraldehyde diacetate, isobutyraldehydediisobutyrate, isobutyraldehyde dipropionate, 2-ethylhexaldehydediacetate, 2-ethylhexaldehyde diisobutyrate, Zcthylhexaldehydedipropionate, .furfuraldiacetate and furfuraldipropionate.

The preferred aldehyde dialkanoates used in the fuel compositions of theinvention are derived from aldehydes containing 1-8 carbon atoms andfrom .aliphatic monocarboxylic acids containing 1-8 carbon atoms.Preferred aldehyde dialkanoates are acetaldehyde diacetate,benzaldiacetate, ;benzaldipropiona-te, acetaldehyde dipropionate,propionaldehyde diacetate and furfuraldiacetate.

The aldehyde dialkanoates must be present in the'leaded aromatic and/orolefin-containing compositions of the invention in a minimumconcentration of 0.1 volume percent :before a significant octaneappreciation is realized. When the concentration of aldehydedialkanoates is below 0.1 volume percent, no .octane improvement isobtained in leaded gasoline containing 10 or more volume percentaromatics and/or olefins. The preferred concentration of aldehyde.dialkanoates in the fuel compositions of the invention fall between 0.2and 2.0 volume percent with maximum octane appreciation generally beingobtained at concentrations between about 0.5 and 1.5 volume percent.Although concentrations of aldehyde dialkanoates as high as 5 volumepercent may be employed with accompanying octane appreciation, economicconsiderations preclude the use of such high concentrations. Inaddition, it appears there is a fall-off in octane appreciation afterthe concentration of the aldehyde dialkanoate exceeds about 1.5 volumepercent.

In the following table there is shown the effectiveness of aldehydedialkanoates as octane apprecia-tors in a leaded base fuel comprisingapproximately percent n-butane, 40 percent isobutane-isobutylenealkylate, 10 percent pentenes from fluid catalytically cracked naphthaand 40 percent heavy platformate. With 3 cc. of tetraethyl lead -(TEL)per gallon, this base fuelhad a Research Octane No. (RON) of 105.Fluorescent Indicator Analysis (PIA) indicated that this base fuel hadan aromatic content of approximately 35 percent and an olefinic contentof approximately 6 percent, its -IBP was 90 F. and its end point was 367F.

T able I Research octane No. Base fuel 105.0 Base fuel +0.25 v. percentbenaldiacetate 105.6 Base fuel +0.5 v. percent benzaldiacetate 106.3.Base fuel +1.0 v. percent benzaldiacetate 107.4

Base fuel +0.25 v. percent acetaldehyde diacetate 105.6 Base fuel +0.5v. percent acetaldehyde diacetate 105.7

Base fuel +1.0 v. percent acetaldehyde diacetate 107.5 Base fuel +0.5 v.percent furfuraldiacetate 106.4 Base fuel +1.0 v. percentfurfuraldiacetate 107.3

percent saturates, 30 percent olefins and 31 ercent aromatics. Thiscommercial premium base fuel contained 3 cc. of TEL per gallon and hadan RON of 99.0.

Table II Research octane N0. Base fuel 99.0 Base fuel +0.5 v. percentbenzaldiacetate 99.2 Base fuel +1.0 v. percent 'benzaldiacetate 99.5

Base fuel +1.0 v. percent acetaldehyde diac etate s- 100.2 Base fuel+0.5 v. percent furfuraldiacetate 99.3 Base fuel +1.0 v. percentfurfural diacetate 99.4

The specificity of aldehyde diacetates in appreciating the octane ratingof leaded fuels containing the prescribed aromatic and/or olefin contentwas demonstrated by the fact that the polyol esters shown in Table IIIwere ineffective in improving the octane rating of a leaded fuelcontaining the prescribed aromatic and/ or olefin content. Table IIIPolyol esters ineffective as octane appreciators in concentrations up to1.0 vol. percent:

Sucrose octaacetate Pentaerythritol tetraacetate Ethylene glycoldiformate Ethylene glycol diacetate Ethylene glycol dilaurate Ethyleneglycol dimyristate Ethylene glycol dipalmitate 2,2,4-trimethyl1,3-pentane diacetate.

Obviously, many modifications and variations of the invention ashereinbefore set forth may be made without departing from the spirit andscope thereof and, therefore, only such limitations should be imposed asare indicated in the appended claims.

We claim:

1. A hydrocarbon fuel in the gasoline boiling range containing anorgano-lead anti-knock agent, at least 10 volume percent of-high octanecomponents selected from the group consisting of olefinic hydrocarbons,aromatic hydrocarbons and mixtures thereof and analdehyde dialkanoate ina concentration of 0.1 to 5.0 volume percent, said concentration beingsufficient to effect substantial improvement of the octane rating ofsaid hydrocarbon fuel said aldehyde dialkanoate having the generalformula:

wherein R is selected from the group consisting of a hydrocarbyl radicalcontaining 1-12 carbon atoms and the furyl radical and R is an aliphatichydrocarbyl radical containing 1-12 and preferably 1-8 carbon atoms.

2. A hydrocarbon fuel according to claim 1 in which said organo-leadanti-knockagent is present in a concen' tration between 0.5 and 4.6 cc..per gallon.

3. A hydrocarbon fuel in the gasoline boiling range containing atetraalkyl lead anti-knock agent in a concentration of at least 0.5 cc.per gallon, high octane components selected from the group consisting ofolefinic hydrocarbons, aromatic hy-drocarbonszmd mixtures thereof in aconcentration of at least 10 volume percent ofsaid fuel, and an aldehydedialkanoate having the general formula: RCH=(OOCR.) wherein R isselected from the group consisting of a hydrocarbyl radical containing1-12 carbon atoms andthe furyl radical and R is an aliphatic hydrocarbyl.radical containing 1-12 and preferably 1-8 carbon atoms, .said aldehydedialkanoate being present in a concentration of 0.1 to 5.0 volumepercent.

4. A hydrocarbon fuel according to claim 3 in which said aldehydedialkanoate is present in a concentration between 0.2 and 2.0 volumepercent.

5. A hydrocarbon fuel according to claim 3 in which said high octanecomponents constitute 20-80 volume percent of said fuel.

6. A hydrocarbon fuel according to claim 3 containing 1.0 to 4.6 cc. oftetraethyl lead per gallon.

7. A hydrocarbon fuel according to claim 3 in which said aldehydedialkanoate is benzaldiacetate.

8. A hydrocarbon fuel according to claim 3 in which said aldehydedialkanoate is acetaldehyde diacetate.

9. A hydrocarbon fuel according to claim 3 is which said aldehydedialkanoate is furfural diacetate.

10. A hydrocarbon fuel in the gasoline boiling range containing atetraalkyl lead antiknock agent, substantial quantities of high octanecomponents selected from the group consisting of olefinic hydrocarbons,aromatic hydrocarbons and mixtures thereof and ethylidene diacetate inan amount sufiicient to improve the octane rating of said hydrocarbonfuel.

References Cited UNITED STATES PATENTS 1,423,049 7/1922 Tunison 44-701,692,784 11/ 1928 Orelup et al 4466 2,145,889 2/1939 Prutton et al.44-66 2,210,942 8/1940 Lipkin 44-77 6 2,228,662 1/ 1941 Holm 44-702,403,268 7/1946 Davis et a1 4469 2,409,156 10/1946 Schulze et al. 44-692,843,607 7/1958 Servigne et al. 260494 2,866,813 12/1958 McLeer 2604942,884,315 4/1959 Barnum 44-56 FOREIGN PATENTS 72 10/ 1958 Trinidad andTobago. 277,326 1/ 1929 Great Britain. 837,965 2/ 1939 France.

OTHER REFERENCES Improved Motors Fuels Through Selective Blending,Wagner et al., paper presented before American Petroleum Institute, Nov.7, 1941, pp. 8-13.

DANIEL E. WYMAN, Primary Examiner.

JULIUS GREENWALD, ALPHONSO D. SULLIVAN,

Examiners.

Y. H. SMITH, Assistant Examiner.

1. A HYDROCARBON FUEL IN THE GASOLINE BOILING RANGE CONTAINING ANORGANO-LEAD ANTI-KNOCK AGENT, AT 10 VOLUME PERCENT OF HIGH OCTANECOMPONENTS SELECTED FROM THE GROUP CONSISTING OF OLEFINIC HYDROCARBONS,AROMATIC HYDROCARBONS AND MIXTURES THEREOF AND AN ALDEHYDE DIALKANOATEIN A CONCENTRATION OF 0.1 TO 5.0 VOLUME PERCENT, SAID CONCENTRATIONBEING SUFFICIENT TO EFFECT SUBSTANTIAL IMPROVEMENT OF THE OCTANE RATINGOF SAID HYDROCARBON FUEL SAID ALDEHYDE DIALKANOATE HAVING THE GENERALFORMULA: